Two-dimensional needle array device and method of use

ABSTRACT

In one aspect, the present disclosure relates to a device for obtaining biological tissue. In some embodiments, the device can include a first row of a plurality of hollow tubes; a second row of a plurality of hollow tubes, adjacent the first row of hollow tubes; a third row of a plurality of hollow tubes, adjacent the second row of hollow tubes, the first, second and third rows forming an array of hollow tubes; wherein each hollow tube can include at least one point at the distal end of the hollow tube, the plurality of rows forming a two dimensional array of hollow tubes; wherein an inner diameter of the at least one tube is less than about 1 mm, the distal end of each of the hollow tubes is configured to be inserted into a biological tissue donor site to remove a portion of tissue therefrom when each of the hollow tubes is withdrawn from the donor site.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 62/151,209, titled MULTIPLE-POINT CORING NEEDLE WITH NARROW HEELS,filed on Apr. 22, 2015, the entire contents of which are incorporated byreference herein.

This application is also related to the following applications, filedDec. 3, 2015, and hereby incorporated by reference:

-   -   “METHOD AND SYSTEM FOR HARVESTING BIOLOGICAL TISSUE” (U.S.        application Ser. No. 14/957,846); and    -   “METHOD OF HARVESTING TISSUE USING SEQUENTIAL SECTIONS OF A TWO        DIMENSIONAL ARRAY OF NEEDLES” (U.S. application Ser. No.        14/958,305).

FIELD

Embodiments of the apparati and methods described herein generallyrelate to a device for harvesting and depositing tissue.

BACKGROUND

Hollow implements, including needles, tubes, cannulas, or the like, maybe used to core or otherwise remove skin or other tissue from a site onthe body. This tissue may be used for a variety of purposes, in somecases as a graft that can be transplanted from one site (e.g., a donorsite) to another site (e.g., a recipient site).

The greater the force required to insert the tube into the tissue site,the greater the possibility of damaging the tissue removed from the siteand the donor site itself. In cases where it is desirable to maintainthe integrity or viability of the tissue, or to otherwise facilitateremoval of the tissue while applying lower force to the donor site, forexample in cases where multiple tubes are applied to the tissue site atthe same time, it may be advantageous to use a tube that reduces theforce required to insert the tube into the tissue site. Conventionalhollow tubes, such as needles, attempt to reduce the force required forinsertion into the tissue site in various ways. For example, needles mayinclude a single or double beveled ends. Double beveled needles mayinclude two sharp points and two elliptical heels, one on either side ofthe needle. Alternatively, needles with zero, one, or more points may berotated to core tissue, or needles may be formed from a low frictionmaterial, or may be coated at least in part with a lubricant. However,the tubes associated with these known techniques may apply a high amountof force on the skin when inserting the tube to remove the tissue.

The creation of 1D, 2D, or 3D arrays using currently availablehypodermic needles involves the positioning or placement of individualneedles—that is, at some point in the process wherein an array is to beformed, each individual needle must be handled and positioned. Suchhandling and positioning requires substantial labor, which, in turn, iscostly in time and money.

BRIEF DESCRIPTION OF THE FIGURES

Various objects, features, and advantages of the present disclosure canbe more fully appreciated with reference to the following detaileddescription when considered in connection with the following drawings,in which like reference numerals identify like elements. The followingdrawings are for the purpose of illustration only and are not intendedto be limiting of the invention.

FIG. 1A is a side view of a double bevel needle.

FIG. 1B is a side view of a double bevel needle, according to aspects ofthe present disclosure.

FIG. 1C is a side view of the double bevel needle of FIG. 1B, rotatedninety degrees, according to aspects of the present disclosure.

FIG. 1D is a side view of another embodiment of a double bevel needle,according to aspects of the present disclosure.

FIG. 1E shows an ellipse and equation for an ellipse.

FIG. 2 is a top view of an array of needles, according to embodiments ofthe present disclosure.

FIGS. 3 and 4 describe a stamp and roll technique for manufacturingneedles, according to embodiments of the present disclosure.

FIG. 5A depicts a pick and place accordion method for manufacturingneedles, according to aspects of the present disclosure.

FIG. 5B depicts a pick and place accordion method for manufacturing pinarrays, according to aspects of the present disclosure.

FIGS. 6A and 6B are photographs of arrays of needles at various stagesof the pick and place accordion method for manufacturing of needles,according to aspects of the present disclosure.

FIGS. 7A-D depict a grafting device including a tissue stabilizer andmethod of operation thereof in accordance with embodiments of thepresent disclosure.

FIGS. 8A-8H depict apparati for the vibratory actuation of a needle,according to embodiments of the present disclosure.

SUMMARY

In one aspect, the present disclosure relates to a device for obtainingbiological tissue. In some embodiments, the device can include a firstrow of a plurality of hollow tubes; a second row of a plurality ofhollow tubes, adjacent the first row of hollow tubes; a third row of aplurality of hollow tubes, adjacent the second row of hollow tubes, thefirst, second and third rows forming an array of hollow tubes; whereineach hollow tube can include at least one point at the distal end of thehollow tube, the plurality of rows forming a two dimensional array ofhollow tubes; wherein an inner diameter of the at least one tube is lessthan about 1 mm, the distal end of each of the hollow tubes isconfigured to be inserted into a biological tissue donor site to removea portion of tissue therefrom when each of the hollow tubes is withdrawnfrom the donor site.

In some embodiments, the array can include a circle. In someembodiments, the area of the circle can be about one square inch. Insome embodiments, the donor site can be an area of about one squareinch. In some embodiments, the tissue withdraw from the donor site canbe about 0.1 square inches. In some embodiments, the array of hollowtubes can be about 300 hollow tubes. In some embodiments, the device caninclude a plurality of pins, each of the pins provided within a centrallumen of each of the hollow tubes. In some embodiments, the device caninclude a stop to limit the depth of insertion into biological tissue ofeach of the hollow tubes in the array of hollow tubes. In someembodiments, the device can include a solenoid, wherein the solenoidactuates the array of hollow tubes to insert the array of hollow tubesinto the biological tissue donor site. In some embodiments, the devicecan include a spring, wherein the spring actuates the array of hollowtubes to insert the array of hollow tubes into the biological tissuedonor site. In some embodiments, the device can include a firstsolenoid, wherein the first solenoid actuates the first row of hollowtubes. In some embodiments, the device can include a second solenoid,wherein the second solenoid actuates in a direction opposite the firstsolenoid. In some embodiments, the device can include a force sensor,wherein the force sensor senses the force with which the device isapplied to the biological tissue donor site. In some embodiments, eachhollow tube can include two points at the distal end of the hollow tube.In some embodiments, each hollow tube can include a narrow heel betweenthe two points. In some embodiments, narrow can include less than about10% of the inner diameter of the hollow tube. In some embodiments, thehollow tube can have an inner diameter of less than about 0.8 mm. Insome embodiments, the biological tissue can include skin tissue andadipose tissue.

DESCRIPTION

The present disclosure relates to a device and method for extractingmicro-sized columns of skin tissue from a donor site and depositingand/or scattering the harvested tissue onto a wound. The depositedtissue promotes healing of the wound site. The device can harvest fromapproximately one square inch of donor site by using several hundredneedles. In some embodiments, the needles used to harvest the tissue canhave narrow heels to provide easier insertion into the donor site. Insome embodiments, the needles can be manufactured using a stamp and rollmethod, while in other embodiments, the needles can be manufacturedusing an accordion method. In other embodiments, each individual needlecan be sharpened and cut and assembled into arrays. In some embodiments,all the needles can be inserted into the donor site simultaneously,while in other embodiments, selected groups of needles can be insertedsequentially. In some embodiments, the needles can be vibrated uponentry into the donor site and/or inserting the harvested tissue into thewound. In some embodiments, the needles can be rotated while insertinginto the donor site.

Multiple-Point Coring Needle with Narrow Heels

FIG. 1A is a side view of a double bevel needle 100. Needle 100 can be acylinder or tube 102 and can include one or more points, for example,two points 104 and 106, that may be formed by grinding or cutting theneedle at an angle on both sides relative to the longitudinal axis ofthe tube 102 to form a bevel 108. Hollow tube 102 can be formed of metalor any other structurally rigid material. Bevel 108 forms what isreferred to herein as an elliptical heel 114. A heel is defined as thesection of the needle where the tangent of the cutting edge is −45 to−90 degrees, and +45 to +90 degrees from the axis of the needle. Asingle bevel needle can have one side with a bevel. A double bevelneedle can have one bevel on one side of the needle and a second bevelon the opposite side of the needle. The angle of the bevel that formstips of the needle may vary, but in one example the angle is about 30degrees, although other larger or smaller angles may be used. Forexample, the angle could be in the range of about 10-35 degrees. Needlepoints 104 and 106 can each have a flat cutting edge, 110, 112 with alength equal to the thickness of the wall of tube 102. In thisembodiment, when the needle is inserted into tissue, sharp points 104,106 can enter the tissue with a relatively low force due to thesharpness of points 104, 106 of needle 102, but elliptical heels 114,which are formed where the proximal portions of the two points convergein the needle body, may result in higher insertion forces, due to theblunt angle at which they contact and enter the tissue. In cases wheremultiple needles are applied to the tissue at the same time, for exampleas a needle array, the force required to insert the array may beincreased relative to the number of needles in the array and couldsignificantly inhibit a user from inserting the array at a tissue siteor cause significant pain upon insertion. In cases where it is desirableto maintain the integrity or viability of the tissue, the additionalforce required to insert the heel of the needle may damage the tissue atthe donor site as well as the tissue that is removed.

FIG. 1B is a side view of a double bevel needle, according to aspects ofthe present disclosure. FIG. 1C is a side view of the double bevelneedle of FIG. 1B, rotated ninety degrees, according to aspects of thepresent disclosure. This needle differs from the needle shown in FIG. 1Ain that it has two bevels on each side of the needle, for a total offour bevels on the needle. The use of two bevels on each side results ina significantly narrower heel 122. The narrower heel 122 can provide asharper cutting edge than prior art needles, thus causing less tissuedamage and pain upon insertion of the needle into the donor site.According to embodiments of the present disclosure, a cutting edge ofthe described needles starts at one of the needle tips and runs backtoward the heel 122, continues through heel 122, and back up to theother tip. In order to harvest tissue with the least impact to thesurrounding tissue and least pain to the patient, the cutting edgeshould be sharp. Sharp, as used herein, means that the tube materialcomes to as fine a point as possible all along the cutting edge. Forexample, a tip whose cutting edge is either a single point, or is a linethat is shorter than the wall thickness of the tube. Further, as usedherein, narrow refers to the width of the heel, while sharp refers tothe width of the cutting edge, e.g., the sharpness of a knife edge.Narrow is defined as the width of the heel being approximately 15% or10% or less of the inside diameter of the cannula or needle. While thepresent disclosure describes a needle with two bevels per side to createeach heel, the disclosed narrow heel could be achieved with more thantwo bevels or with a curved bevel. The disclosed embodiments achieve anarrow heel while not requiring an excessive distance between the heeland the tip. Accordingly, the bevel angle, where it crosses the internaldiameter of the tube should be as shallow as reasonably possible. Insome embodiments reasonably possible refers to an acceptable length fromthe heel to the tip. A shallower angle will provide a narrower heel, butwill also create a longer distance from heel to tip. The intended use ofthe needle can determine the acceptable length. For skin harvesting,that distance can be kept under about 2 mm.

With reference to the equation of ellipse shown in FIG. 1E, to achieve a“narrow” heel, the present disclosure seeks to make c (the distance fromthe center to one of the foci of the ellipse, i.e., the bevel) as longas is reasonable without having the needle tip become too long, and havethe ratio of a over c as close to 1 as is reasonably possible. This isbecause as the device cores, the needle is pushed into the tissue.Therefore, when the tissue is up away from the heel, the direction oftravel creates a slicing effect as with a knife. When the base of theheel is reached, the cutting edge is perpendicular to the pushingdirection, which requires more force to cut through the tissue. A“narrow heel” keeps the angle made between the cutting edge and the axisof the needle less than 45 degrees as long as possible (as close to theheel as possible). This keeps the slicing effect as long as possible.

As can be seen in FIGS. 1B and 1C, a distal end of tube 102 can beshaped to form points 110, 112. As shown in FIG. 1C, a first bevel 124and a second bevel 120 are formed on the front and back of the distalend of tube 102. Second bevel 120 forms tips 110, 112, or points of theneedle. First bevel 124 in conjunction with second bevel 120 formsnarrow heel 122.

With continued reference to FIG. 1C, to form first bevel 120, the frontand back sides of the distal end of tube 102 can each be ground or cutat an angle relative to the axis of the tube 102, e.g., to form abeveled structure at the distal end of tube 102. For example, anexemplary tip angle is about 30 degrees as shown in FIG. 1C correspondsto an angle relative to the axis of the tube, a, of about 15 degrees.Though angle α in this example is about 15 degrees, angle α may belarger or smaller than 15 degrees. For example, angle α may range fromabout 10 degrees to about 18 degrees.

The second bevel angle 124 on each side of tube 102 is generallyshallower than first bevel 120, and forms sharpened heel 122 shown inFIG. 1B. The angle of second bevel 124 relative to the longitudinal axisof tube 102, can be 6 degrees and can create a tight, narrow ellipsethat approximates a point at the heel 122 on each side of the needle asseen in the front view in FIG. 1B.

In one embodiment, second bevel 124 can be formed by grinding or cuttingthe front and back sides at the distal end of the tube 102 at an angle βrelative to the axis of tube 102. The second angle β is shallower thanthe first angle α to form a narrow ellipse that approximates a point atthe heel 122 of the needle tip. Though second angle β in this example isabout 6 degrees, angle β may vary, so long as second angle β isshallower than first angle α. In alternative embodiments, the needle maybe formed with more than two bevel angles. For example, three or morebevel angles may be formed on each side of the tube, with the degree ofthe bevel decreasing, the further the bevel is from the distal end ofthe tube. In further alternative embodiments, the two or more angles maybe formed on each side of the tube by way of forming a curved surface oneach side of the tube where the angle of the curve varies along thelength of the tube. In some embodiments, the narrow heel can be achievedwith only one bevel per needle side. However, the singular bevel wouldneed to be a shallow angle up to the tip of the needle, which maygreatly increase the distance from heel to tip of the bevel.

With continued reference to FIGS. 1B and 1C tube 102 has two tips 110,112 that can be formed by grinding opposite sides of tube 102 at a firstbevel angle α relative to the long axis of the tube 102. The two tips110, 112 have inner cutting edges 111, 113 that converge at a point, ornearly a point 122 at the heel of the needle tip. Inner cutting edges111, 113 are formed from the inner wall surface of the tube, which isexposed by first bevel 120. A tube with two tips 110, 112 will have fourinner cutting edges, two associated with each point. Though the cuttingedges 111, 113 on the front of tube 126 are shown in FIG. 1B,corresponding cutting edges on the back of tube 102 are not shown. Insome embodiments, the inner cutting edges may be further sharpened byapplying an additional bevel to the inner or outer wall surface of thetube, or to both the inner and outer wall surfaces. Further sharpeningthe inner wall edges enables the tube to pass through tissue with alower force slicing motion. The narrow point at heel 122 is formed fromthe shallow second bevel 124 described with reference to FIG. 1C. Bynarrowing cutting edges 111, 113 to a point or nearly a point at heel122, the cutting edge of the needle can continue slicing the tissue asthe needle is inserted and the force required to insert the needle intothe tissue is decreased compared to double bevel needles without asharpened heel. Unlike FIG. 1A, where heel 114 is curved, and the vertexis almost parallel to the flat distal ends of tips 110, 112, in theembodiments shown in FIGS. 1B-D, only a small section of the cuttingedge, at the vertex of the ellipse, is pushed perpendicularly into thetissue. By minimizing the area of the vertex and forming it with anangle, the force required to insert the tube into tissue is lowered, andthe tube is able to slice tissue with inner cutting edges 111, 113 alongtheir length as the tube is inserted into tissue.

FIG. 1D is a side view of another embodiment of a double bevel needle,according to aspects of the present disclosure. As further shown in FIG.1D, a third bevel 144 and a fourth bevel 146 can be optionally providedin a direction orthogonal to the first and second bevels 120, 124. Theseadditional bevels are characterized by the angle λ which represents theangle at which each of the opposing lateral sides of the tube 102 can beground or cut relative to the longitudinal axis of tube 102. In theexemplary embodiment, angle λ can be about 6 degrees but it may belarger or smaller, for example between about 3 and about 9 degrees.These bevels 144, 146 can be provided to reduce the size or width of thesharp edge of the tips 136, 138 formed at the end of the tube 102 tofurther facilitate insertion of the tube 102 into a donor-site tissue.The depth of bevel may vary. For example, bevel may be shallow, leavinga flat cutting edge at points 136, 138, or bevel may be deeper such thatthe tips form sharp points as shown in FIG. 1D. The angle of bevel mayvary as well. The points or extensions 136, 138 formed from angle λ thatform a narrow angle at their tip as shown in FIG. 1D can be insertedinto the tissue using a smaller force as compared to points formed froman angle larger than λ, although this force may be applied for a longerdistance and/or time to achieve full insertion of the tube 102 into thetissue than that used for tips formed from a larger angel λ thus have ashorter length of the angled tip region.

Though the exemplary embodiment shown in FIGS. 1B-1D discloses a tubewith two points and two heels, further embodiments may include tubeswith any number of points and heels greater than one. For example, in afurther exemplary embodiment, a tube can be provided with three pointsor extensions provided at a distal end thereof. This exemplaryconfiguration can be formed, e.g., by grinding three portions of thetube at a first angle α relative to the long axis thereof, where thethree portions can be spaced apart by about 120 degrees around theperimeter of the tube. In still further exemplary embodiments, a tubecan be provided that includes more than three points or extensionsprovided at a distal end thereof, e.g., a tube having four, five, six,seven, eight, or more points. In this configuration, one or more of theheels may be formed with a second shallower angle relative to firstangle α to form one or more sharpened heels as described in the presentdisclosure. The second angle may be different for each heel on the tube.The initial force needed for the tube to penetrate the tissue can beapproximately proportional to the number of points if the angle of eachpoint or extension is held constant. Providing a greater number ofpoints extensions at the distal end of the tube can improve mechanicalstability of the tube and/or geometrical control of the severed tissue,but it may use a larger force to penetrate the tissue. However, if theneedle points are sharper because the angles are lower, a system with agreater number of needle points can actually have lower overall forcethan existing systems with fewer, duller needle points.

The various geometries and points described herein can be used in any ofthe exemplary embodiments of the present disclosure, e.g., for thevarious devices and methods described herein. For example, the hollowtube can be provided with a bevel angle α of less than about 15 degrees,e.g., about 12 degrees. Such an acute tip angle can provide sharp tipsof the points or extensions that can more easily penetrate a biologicaltissue or matrix material. A narrower tip angle α, e.g. about 6 degrees,may be preferable for harvesting and/or inserting micrografts in adenser or tougher tissue or matrix material, where the narrower tips ofthe points or extensions can be configured to more easily cut throughthe tissue or matrix material when the tube is inserted therein. Asecondary bevel having an angle λ, such as the exemplary tips of thepoints or extensions shown in FIG. 1D, can further facilitate insertionof the distal end of the tube into various materials by providing thetips of the points or extensions that are smaller and more pointed.However, the tips of the points or extensions that are sharper and/ornarrower, e.g., those having small tip angle α and/or a secondary bevelwith angle λ, can also be more prone to wear, bending, or otherdeformation, if the tube is repeatedly inserted into tissue or a matrix.Accordingly, the tip geometry selected for a particular application canbe selected based on the type of material or tissue the apparatus willbe used with, as well as the desired lifetime of the tube.

The inner diameter of the tube can be selected or structured toapproximately correspond to a particular diameter of a tissue portionsuch as a micrograft to be removed from a donor site. According to oneexemplary embodiment, the inner diameter of the tube can be less thanabout 1 mm. For example, 18 or 20 gauge biopsy needles (e.g., having aninner diameter of 0.838 mm and 0.564 mm, respectively) or the like canbe used to form the tube. A biopsy tube having a larger gauge (andsmaller inner diameter) can also be used. Based on the interactionbetween the tube, width or diameter of the harvested tissue can beslightly smaller than the inside diameter of the apparatus used toharvest it.

Living tissue can be provided with nutrients via a diffusional transportover distances of about 0.1 mm. Accordingly, tubes according to thepresent disclosure may be configured to extract exemplary micrograftshaving at least one dimension that is less than about 0.6 mm, e.g., lessthan about 0.3 mm or, e.g., less than about 0.2 mm, which can exhibitimproved viability and likelihood to survive, and they may grow whenused in a graft. Such exemplary micrografts can be better able toreceive nutrients (including, e.g., oxygen) when placed in a recipientsite, prior to revascularization of the tissue.

Tubes according to the present disclosure may also be configured toextract larger micrografts, e.g., those having a width of about 1-2 mm,which can also benefit from such diffusional transport of nutrients, andcan also be more likely to survive than significantly larger portions ofgraft tissue (e.g., conventional full-thickness, split-thickness ormeshed grafts). These larger sizes can be preferable for harvestedtissue that is heterogeneous, e.g., tissues that may contain certainstructures that can be preserved within a single micrograft. Forexample, skin tissue has certain structures such as hair follicles,sebaceous glands, etc., and harvesting somewhat larger micrografts fromskin may help to preserve these tissue structures when harvested andtransplanted. On the other hand, smaller micrografts, e.g. those lessthan about 0.6 mm, or about 0.2 mm wide, can be suitable for relativelyhomogeneous tissues, such as muscle tissue, where there are few or nolarger structures in the tissue to be preserved.

In embodiments where a tube as described in the present disclosure isused to harvest micrografts, a width or diameter of the holes at thedonor site produced during harvesting (which can correspondapproximately to the diameters of the portions of harvested micrografts)can be less than about 2 mm, or less than about 1 mm. In certainexemplary embodiments of the present disclosure, the tube may beconfigured to extract a micrograft having a diameter or width of lessthan about 0.6 mm, less than about 0.3 mm, or about 0.2 mm. The size ofthe exemplary holes at the donor site can be selected, e.g., based onthe effects of creating small damage regions in the donor site that canheal rapidly and/or without scarring, and on creating portions of tissuethat can be small enough to promote viability when transplanted orplaced in a growth medium, and large enough to form a sufficient amountof graft tissue and/or capture tissue structures that may be present inthe donor tissue. The advantageous sharp heel design described in thepresent disclosure can further minimize damage to the donor site tissueby limiting the amount of force required to insert the tube into thedonor site, thereby decreasing tissue morbidity.

Other aspects of a cannula, tube or needle having the propertiesdescribed herein may be realized as well. In one embodiment, the cannulamay be used to harvest or extract graft tissue. In this embodiment, thecannula is configured to remove tissue from a donor site, and facilitateplacement of the tissue at a recipient site. Placement of the tissue ata recipient site may be performed by inserting the cannula at therecipient site, or otherwise expelling the tissue from the cannula anddepositing, placing it, or otherwise distributing the tissue at therecipient site. The recipient site may be another location on the sameindividual as the donor site, a different individual, or it may beanother material such as a matrix. In some cases the matrix may be abiocompatible matrix, which may form a graft or larger copy of the donortissue, such as that described in U.S. patent application Ser. No.13/102,711, the entirety of which is incorporated herein by reference.U.S. patent application Ser. No. 12/936,173 is also incorporated byreference in its entirety.

In some embodiments, the tube may also include a collar or stop or thelike provided on an inner or outer surface of the tube or may otherwisebe affixed to an apparatus holding the tube such that it limits theinsertion depth of the tube. In some embodiments the stop may comprise asensor, camera or other mechanism that prevents the tube from extendingpast a particular depth. In one embodiment, the stop or other mechanismmay be affixed to the tube at a particular distance from the ends of thetips, or this distance may be adjustable, e.g., over a range of lengthsby moving the stop along the axis of the tube. In one example, a stopmay be positioned on the tube to allow insertion of the tube up to thedermal/fatty layer of the skin.

In one example, the tube may be inserted into the tissue at the donorsite, and the tips and cutting edges and may sever a tissue portion fromthe surrounding tissue as the tube penetrates the donor site tissue. Thetube may be inserted to a specific depth, e.g., until a stop contactsthe surface of the donor site. A portion of tissue can be present withina lower portion of the tube. Such tissue can remain within the tube, andbe separated from the donor site with the tube to form a micrograft whenthe tube is removed from the donor site. The exemplary micrograft thusformed can include both epidermal tissue and dermal tissue. For example,a micrograft can be removed from a donor site by removing the tube,including the micrograft, from a donor site without rotating the tubearound the axis thereof and without suction. The points or extensionsprovided on the tube can facilitate such removal of micrograft tissuefrom the surrounding tissue at a donor site.

A micrograft or other tissue may be removed from the tube in a varietyof ways. For example, by providing pressure through an opening at aproximal end of the tube. Such pressure can be mechanical, hydraulic,pneumatic, etc. For example, the pressure can be provided by blowinginto the opening, by squeezing a flexible bulb attached to the proximalend of the tube, by opening a valve leading from a source of elevatedpressure such as a small pump, etc. In other embodiments, the tissue canbe removed from the tube by using the pins disposed within the tubes topush the grafts out of the tubes. Alternatively, tissue such asmicrografts can be harvested by inserting the tube into a plurality oflocations of a donor site. Each micrograft within the tube can then pushany micrografts above it towards the proximal end of the tube, which maybe open or coupled to a receptacle configured to store the micrograftsfor transport. Once the tube has been substantially filled with theharvested tissue, each additional insertion of the tube into the donorsite can facilitate pushing of an uppermost micrograft within the tubeout of the proximal end or into the receptacle or other collectiondevice. Other mechanisms, such as vibration, may be used to remove themicrografts from the tube as well.

In embodiments where the cannula is inserted into and/or pierces therecipient site to remove the tissue, the exemplary configuration of thetube distal end, including the reduced dimensions of the heel to a pointor a near point, such that the cutting surface is at an angle to thetissue for as long as possible, is advantageous to the recipient site inaddition to the advantages realized at the donor site. For example,trauma is reduced at the recipient site when the cannula is insertedtherein for the same reasons discussed previously with respect to thedonor site.

In an alternative embodiment, the cannula may be used in conjunctionwith a piercing cannula. In this embodiment, the cannula may be disposedinside a piercing cannula and advanced through the piercing cannula todeposit tissue at a recipient site. The piercing cannula may alsoinclude at least one narrow heel as described in the present disclosure.

Many advantages over conventional cutting or piercing tubes or cannulasmay be realized by the apparatus of the present disclosure. In oneembodiment, an apparatus may be provided that includes a plurality oftubes, each having sharpened heels as described in the presentdisclosure. The plurality of tubes may be mechanically affixed orotherwise coupled to a base to form an array of tubes. In thisconfiguration, multiple portions of tissue may be harvested from a donorsite simultaneously, or near simultaneously, by a single insertion ofthe array of tubes into the donor site. The array may be formed in anumber of configurations, including in linear array, or in any form of apattern along the base. The spacing of tubes in the pattern may beregular or somewhat irregular or varied, which may both facilitateinsertion of the array at the donor site and may also avoid formation ofpatterns at the donor site. The needle array spacing can be chosen tofacilitate insertion and also, in some embodiments, to avoid collateraldamages, e.g., tearing, to the surrounding tissue.

Generally, a greater number of tubes in the array corresponds to agreater force required to insert the tubes into tissue or a matrixsimultaneously, which may be undesirable if the force is too large.However, when needles having the narrow heel discussed in the presentdisclosure are assembled into arrays of needles that are to be insertedinto a donor site for the purpose of harvesting tissue, the amount offorce required to insert the array into the patient isdisproportionately low compared to arrays of conventional needles thatdo not have narrow heels. The apparatus of the present disclosure alsocreates a donor-site wound that is much less substantial than ifperformed using conventional implements, thus resulting in much lesstrauma at the donor site and greater patient comfort. These unexpectedadvantages allow for larger arrays that may have more than tens orhundreds of needles, which result in a tool that can harvest largerareas of tissue while minimizing donor site morbidity and pain to thepatient. The dispersion of the needle array can reduce tissue damage andprovide cleaner coring of the donor site.

For example, FIG. 2 is a top view of an array of needles 200, accordingto embodiments of the present disclosure. Array 200 is circular andcontains 316 needles and has an area of approximately one square inch.In the example of FIG. 2, 21 gauge regular wall hypotube needles areused with pins having an outer diameter of approximately 0.018 inches.The needles are spaced 0.056 inches from center and the circle has adiameter of about 1.13 inches. This configuration of needles can resultin a harvest corresponding to 10% area of the harvest site, that is, thetotal cross-sectional area of the 316 tissue columns equals 0.1 squareinches, which is 10% of one inch. Needle density in the array can rangefrom about 1% to about up to 20%, for example, 10% density.

The circular array is formed by assembling a plurality of rows ofneedles, either horizontal or vertical rows. This design is modular andthe configuration can take on any shape or size using various size rowsas modules. In some embodiments, all of the needles can be actuated,e.g., inserted into the tissue, simultaneously. In other embodiments,groups or sections of needles can be actuated sequentially. For example,the array can be divided into quadrants and each quadrant can besequentially actuated. Sequentially can refer to actuating each row in alinear order, (e.g., row1, row2, row3), or non-linear (e.g. row1, row10,row3). Or, each row of needles can be separately and sequentiallyactuated. Finally, each single needle could be separately andsequentially actuated. In some embodiments, the circular array ofneedles can be divided in to a plurality of pie wedges, e.g., three,four, five, six or more wedges, and each wedge can be sequentiallyactuated. In some embodiments, two or more arrays can be actuatedsimultaneously and other arrays can be actuated individually or ingroups until all needles are actuated. In some embodiments, one row isactuated at a time, e.g., 20 rows are individually actuated in sequence,while in other embodiments, two, three, four or more rows can beactuated at a time. An advantage to sequentially actuating segments ofthe array is that insertion of a segment can require less force on thedonor site than insertion of the entire array, which may result in lesstrauma at the donor site. In some embodiments, the array is driven usinga solenoid. Multiple actuations using the solenoid can sequence theinsertion line by line. In some embodiments, two solenoids can be used,each solenoid firing in opposite directions to prevent kick back of thedevice, and further reducing force applied to the donor site and therebyreducing trauma to the surrounding tissue.

Generally, exemplary tubes may include a pin provided in the centrallumen or opening of the tube. The diameter of the pin can besubstantially the same as the inner diameter of the tube or slightlysmaller, such that the pin can be translated along the axis of the tubewhile filling or occluding most or all of the inner lumen of the tube.In some embodiments, the pin can be formed of a low-friction material,or coated with a low-friction material such as, e.g., Teflon® or thelike, to facilitate motion of the pin within the tube and/or inhibitaccumulation or sticking of biological material to the pin. The distalend of the pin can be substantially flat to facilitate displacement ofmicrograft tissue within the tube when the pin is translated. In afurther exemplary embodiment of the present disclosure, an apparatus canbe provided with a plurality of the tubes and of the pins. All of thetubes can be translatable with respect to the pins together using asingle actuator, or certain ones of the tubes can be translatedsimultaneously and/or sequentially using a plurality of the actuators.

In some embodiments, for harvesting tissue the needles are firstinserted to full, specified depth at the location selected forharvesting. In some embodiments, the depth of insertion can be limitedby the use if a hub. All of the needles can be bonded into a “hub” or“stop” (discussed above) and the hub limits the depth because when ithits the skin the penetration of the needles stops. In some embodiments,the needles can be inserted into the skin at a high speed through theuse of a solenoid. In some embodiments, the needles can be insertedusing a loaded spring or any other means that releases or provides ahigh energy impact. When the needles enter the harvest location, a skincolumn is formed within the hollow space of the needle. Once the needleshave been inserted into the tissue to the appropriate depth and thetissue columns are present within the needles, the user removes thedevice from the harvesting area. The tissue columns remain in placewithin the needles. Then, the user transports the device, with theharvested columns to the wound site for depositing. Depositing can beachieved by either inserting the tissue columns into the wound or woundmatrix, or by dropping (scattering) the tissue columns onto the surfaceof the wound.

For inserting, the user positions the device over the wound, and pressesthe needle array into the wound, wound dressing, or wound matrix. Oncethe needles with tissue columns are inserted, the needles are retracted,keeping the pin tips at the surface of the wound location. This holdsthe previously harvested tissue columns in place while the needle areretracted. Then, the device is pulled away from the wound location, andthe tissue columns have been inserted at the wound site. The retractionof the needles pushes the tissue columns out of the needles. Forscattering, the user positions the device over the wound, retracts theneedles, and actuates the solenoid (or other actuation method) again,which causes the needle tips to extend down the length of the pins andpush the tissue columns off the pins. Then the needles stop quickly andretract again, which throws the tissue columns from the tips of theneedles.

The exemplary tubes of the present disclosure may be formed of anysufficiently strong material that is preferably biocompatible or inertwith respect to biological tissue, e.g., a 304 stainless steel, asurgical stainless steel, etc. In some embodiments, the tube can becoated with a lubricant or low-friction material, such as Teflon®, tofurther facilitate the passage of the tubes through tissue. Bevels andother sharp edges may be formed by cutting, grinding, etching, photoetching, electropolishing, or the like. Further finishing processes canbe applied to the tube 20, such as electropolishing, to increasesharpness of the cutting edges, or providing a ME-92® chromium coatingto increase the material strength. Such finishing processes can increasethe cutting effectiveness and/or improve the useful service life of thetube.

The above-described methods for harvesting and scattering tissue can beimplemented using the described narrow heeled needles or any other typeof harvesting apparatus, for example, needles having only one or twobevels, without a narrow heel.

Method of Manufacturing Coring Needles

The previously described needles can be manufactured via a plurality ofmethods, including (1) grinding individual tubes (2) a stamp and rolltechnique and (3) an accordion method. The latter two methods will bediscussed below.

Stamp and Roll

In one embodiment, a stamp and roll method can be used to create aneedle structure from a flat sheet of material. Through the stamp androll method, 1D, 2D, and 3D arrays of needles and associated structurescan be created. For purposes of this discussion, a 1D array can bedefined as an arrangement of needles wherein the needle points arepositioned in a line or curve in space, with equal spacing betweenneedle points, or with a repeating pattern of variable spacing; 2D arraycan be defined as an arrangement of needles wherein the needle pointsare positioned in a plane in space, with a repeating pattern of spacingbetween needle points; 3D array can be defined as an arrangement ofneedles wherein the needle points are positioned over a threedimensional surface in space, in a repeating pattern of spacing betweenneedle points.

Currently, hollow needles, and particularly, hypodermic needles, arefabricated from cylindrical tubing. This imposes limitations on thefinished geometry of the needles based on manufacturing methods offorming hollow tubes, and structural integrity of hollow tubes. Inaddition, the creation of 1D, 2D, or 3D arrays using currently availablehypodermic needles involves the positioning or placement of individualneedles—that is, at some point in the process wherein an array is to beformed, each individual needle must be handled and positioned.

The described method permits the creation of needles of any geometrythat can be conceivably derived from a flat sheet of material that iscut and folded, rolled, bent, twisted, or otherwise formed. Furthermore,the described stamp and roll design achieves arrangements of amultiplicity of such needles in a regular pattern in space, with a highdegree of precision and without the requirement to handle or positionindividual needles.

In the electronics industry, for example, conductive connector pins aretypically manufactured from flat metal ribbons using a process sometimescalled “stamp and roll.” Typically, the metal ribbon is paid-out from areel, and fed continuously into a machine wherein the components are cutand formed, and the finished components are then spooled onto a take-upreel. By virtue of this manufacturing process, the finished componentsare spaced equally along the ribbon. Each connector pin is designed tobe easily broken off of the ribbon (the unused portion of the ribbon iscalled the “carrier”) and the loose pins are then available forincorporation into plastic connector housings. The carrier, or carryingweb, is a processing item that is normally discarded in standard stampand roll processing, after the formed parts are removed from it.According to some embodiments, however, the present methods do notrequire the removal of the needles from the carrier. Instead the carriercan be used to hold the needles together in the array and can be anintegral part of the needle array. Accordingly, in some embodiments, thecarrier can automatically be part of the line of needles formed in thestamp and roll process, and can serve the same purpose as the carrierthat can be added to the needles in other array forming processes.

The needles disclosed herein may be manufactured using the “stamp androll” process, but are not limited to that process. Furthermore, notethat in the device disclosed herein the carrier may be optionally (andadvantageously) designed to be an integral part of the finishedassembly, rather than discarded.

FIGS. 3 and 4 describe a stamp and roll technique for manufacturingneedles, according to embodiments of the present disclosure. Thedisclosed stamp and roll technique can include the following steps, asillustrated in FIGS. 3 and 4:

-   -   1. providing a sheet of material; (302)—not shown in FIG. 4    -   2. stamping a needle design into the sheet of material, (304);    -   3. processing the stamped needle design; (306) and    -   4. rolling the stamped, processed needle design to form an array        of needles having at least one sharp tip and at least one narrow        heel, wherein the needle remains attached to the carrier (308).

In some embodiments, the needle design can include a plurality ofneedles to be formed and can include both a carrier and a needle. Insome embodiments, the resulting needle can include at least one narrowheel and at least one needle tip. In some embodiments, the above methodcan be performed using a machine or manufacturing apparatus. The machineor other manufacturing apparatus may include a processor, software orother non-volatile memory programmed to perform the above steps.

According the stamp and roll technique, several advantages can beachieved. For example, the needle geometry can be formed from a flatsheet of metal, rather than limited by the manufacturing constraints ofhollow tubes, and the stamp and roll technique also can allow forcomplex needle geometry. For example, in one embodiment, the design canhave a flat portion of the structure at the top, an open funnel-likestructure below the top, a substantially closed cylindrical structure inthe middle, and a double-pointed structure at the bottom tip. Further,these techniques can allow for a multiplicity of needles to be formedwith a precise spacing between needles, and the number of needles in the1D array may be of any number. In some embodiments, a given length ofthe 1D array (for example, a length consisting of 20 elements) may bestacked or layered with additional given lengths to form a 2D or 3Darray. The spacing between 1D portions of the 2D or 3D arrays may becontrolled by placing material spacers between the layers. A furtheradvantage is that a wide variety of geometric arrangements ofneighboring layers are possible, including square lattice, triangularlattice, hexagonal lattice, etc. For example, any portion of the arraymay be bonded, encapsulated, or otherwise incorporated into a largerstructure with the intention of imparting support, strength,orientation, or other properties to the whole.

Another advantage of the described manufacturing method is that bothsurfaces of the flat starting material are readily accessible prior toneedle formation, permitting a wide variety of surface treatments,including coating, texturing, ribbing, anodization, etc., any or all ofwhich may be included in the design of the inner or outer surface of theneedle. Further, all edges of the needle are accessible prior to needleformation, permitting a wide variety of edge contours (e.g. single andmultiple needle points; abutting, overlapping, interlocking, scallopedseams, helical seams, etc.) and a wide variety of edge treatments,including coined, beveled, serrated, sharpened, deburred,electro-polished, etc.

In some embodiments, a given length of the 1D array may be further bentor formed, for example back onto itself to form a layered 2D or 3Darray. For example, a given length of the 1D array may be further bentor formed, for example into a circle, with the needle points orientedradially, or into a circle with the needle points oriented orthogonal tothe plane of the circle, or, in general, along any curve in space. Sothat, in principle, any 3D surface may be populated with needle points.In some embodiments, the stamp and roll method can create a singlepoint, a double point, or a triple point needle. The resulting needlecan have any number of points desired and stamped into the sheet beforerolling. In some embodiments, the needle does not have a point at all.

In some embodiments, the 1D needle array may be subjected to secondaryprocesses (for example immersive or spray coatings, chemical sharpening,welding or secondary closure of seams, etc.) as a unitary structure,permitting parallel processing of a multiplicity of elements. Asdescribed herein, the stamp and roll technique allows for the formationof extremely narrow heels because there are no tubular geometryrestrictions. Because this technique does not involve sectioning acylinder, it does not limit the heel to being an ellipse; for example,the heel may be formed into an angular shape. Accordingly, thenarrowness of the heel of a needle made according to these techniques isonly limited to how narrow it be made while sharpening a flat sheetbefore forming the needle. For example, a heel can be made in the shapeof a point, instead of a radiused heel, by forming the heel with theseam of the needle.

Further advantages of the described stamp and roll method includeprecise, repeatable, and low-cost means of forming complex needlegeometries. The various needle geometries can include single or multiplepoints of virtually any shape. The described methods can createnon-cylindrical cross-sections, e.g., a square or any other geometricalshape, flared tops (for easy insertion into the needle bodies, forexample insertion of an obturator) and other unusual or difficultgeometries. The disclosed method also can provide for textured insideand outside surfaces of the needles.

Pick and Place Accordion Method of Manufacturing

Another method for manufacturing needles and needle arrays can include apick and place accordion method. This method can be used to create 1D,2D, and 3D arrays of needles and associated structures. According tothese methods, needles or their precursor materials are handled ingroups comprised of more than one needle, where said handling mayinclude, but is not limited to, positioning, stacking, mounting, andfixturing. In some embodiments, these methods can be performed using amachine or other manufacturing apparatus. Through use of this method,the spacing between needles may be efficiently, accurately, andprecisely established. In some embodiments, the spacing may be regularor patterned, and can extend over 1D, 2D, or 3D space.

The accordion tubes used in this manufacturing method can bemanufactured using various conventional wire-forming processes, such asis used for springs and other complex wire-like structures. Theseprocesses include automated versions which typically consist of (1)pinch-rollers which provide a mechanism for the continuous feed of rawmaterial, and (2) computer numerical control (“CNC”) bending and formingtools, which permit the manipulation and shaping of the continuouslength of raw material. The disclosed accordion method can use anautomated wire-forming process that is augmented as described in thisdisclosure, but is not limited to that process.

According to aspects of this method, needles or their precursormaterials are processed in groups of more than one needle. As usedherein, processing may include but is not limited to grinding, welding,brazing, deburring, sharpening, texturing, and polishing. Groups ofneedles may be ganged or stacked to form larger groups or arrays, saidlarger groups also, optionally, possessing accurate and preciseinter-needle spacing.

FIGS. 5A and 5B depict a pick and place accordion method formanufacturing needles, according to aspects of the present disclosure.In some embodiments, a length of tubing is folded or bent into anaccordion shape, as shown at 502 in FIGS. 5A and 5B. The number of bendsmay range from a single bend to many. The cross-sectional integrity andthe straightness of the folded tubing is maintained within a “criticalzone” that lies between the bends. For example, at the bends of theaccordion shape, the cross section of the tube will deform and not beround. As needles should be round if round pins are used, in someembodiments, the straight sections can be long enough that the bends,and any deformed sections close to the bends are removed, leaving enoughmaterial for an appropriate needle length.

The bend radii of the folded shape are such as to facilitate insertionof the piece into a needle array spacer or carrier 508, as shown at 504.In some embodiments, the bend radii can be about one half the desiredcenter-to-center spacing of the needles, for example, about 0.056inches. In some embodiments, the carrier can be composed of stainlesssteel. In other embodiments, the carrier can be made from a plasticmaterial. Many different clamping arrangements may be employed totemporarily secure the folded shape in carrier 508. In some embodiments,as shown in FIG. 5A, carrier 508 is affixed to the tubing in a locationthat does not encompass an end portion of the tubing. In FIG. 5B,carrier 508 can be affixed to one end of the tubing. The folded shapemay be tightly held by carrier 508 (for example, by mechanical meanssuch as by an interference fit with the grooves, or by a snap actioninto the grooves) or it may be permanently secured to the carrier 508 ina variety of ways, including welding, bonding, insert-molding andbrazing.

In some embodiments, the carrier can include registration holes.Registration holes are holes in the carrier such that the carrier can beattached to other carriers or to something else. In some embodiments,the registration holes can be used to stack lines of needles to makedifferent shapes. In some embodiments, the thickness of the carrier canbe important because the spacing between lines of needles can be madefarther or closer when multiple carriers are stacked. Other means ofregistration, for example, shoulders, pins, etc., are possible as well.The carrier is designed to impart the desired spacing betweenneighboring tubular sections, both within the grouping (by means of thecenter-to-center spacing of the grooves of the carrier) and betweengroupings (by means of the registration holes, and the thickness,length, and, width of the carrier).

Once a single folded shape (or, optionally, several shapes) is/aresecured within one or more carriers, the folded shape is processed, asshown at 506. Examples of processing can include but are not limited tocutting, grinding, sharpening, beveling, texturing, polishing,deburring, shaping, bonding, and welding. In some embodiments, thesingle folded shape, or multiple shapes, can be processed to form anarray or sub-array of needles, with a precise inter-needle spacing andin a precise geometric relation with respect to the carrier. Duringprocessing, the sub-assembly, comprising the single folded shape (ormultiple folded shapes) and the carrier, along with other fixturingcomponents, is processed as a unitary structure, permitting parallelprocessing of a multiplicity of needle elements.

In some embodiments, sub-arrays may be stacked or ganged to form largerarrays. Stacking may be done before or after processing of sub-arrays.As discussed above with respect to FIG. 2, a wide variety of geometricarrangements of neighboring layers are possible, including squarelattice, triangular lattice, hexagonal lattice, etc. Any portion of thearray may be bonded, encapsulated, or otherwise incorporated into alarger structure with the intention of imparting support, strength,orientation, or other properties to the whole. The same fixturing (asshown in FIG. 5B) and forming methods may be used to form wire arrays,which may be used in conjunction with the needle arrays, for example, asprecisely matched ejector pins. Wire and tube arrays may be formed inseparate steps or in the same step. If formed in the same step, the wiremay be threaded through the tubing before forming. The combination oftubing and wire would then be processed together (bent, ground, etc.),with the possible advantage of eliminating a later-stage assembly step.FIGS. 6A and 6B are photographs of folding tubing in the carrier andprocessed needles, respectively. In some embodiments, this “accordion”method can also be done without bent accordions. For example, longstraight sections of tubes can be placed and bonded on several carriersat once. Once these are formed, the sections apart can be cut apart (onecarrier per section) and then sharpened.

Tissue Stabilization

In some embodiments, a tissue stabilizer is implemented to applypressure and stabilize the tissue at the donor site during extraction.Applying pressure to the donor site, for example, with the tissuestabilizer may reduce the amount of force required for the needles orarray to penetrate the donor site, and thereby may reduce trauma at thedonor site. FIGS. 7A-D depict a grafting device having a tissuestabilizer and method of operation thereof in accordance withembodiments of the present disclosure. FIGS. 7A-D depicts a strap as atissue stabilizer. However, in embodiments that do not have the strap,the grafting device can be stabilized with a plastic housing that isaround the needle array. The plastic housing can be composed of hard orsoft material, can be combined with a softer, flared material thatcontacts the skin, and can be shaped such that in the event of multipleharvests, the housing can be lined up with an outline left from priorharvests—to minimize the harvest region/area. The plastic housing pushesagainst the skin to stabilize the skin and hold it down before andduring harvesting. The strap can be used to assist in holding theplastic housing against the skin. Accordingly, the device is stabilizedby having the user apply the pressure and stability of the device on thetissue site, for example, an arm, leg or any other harvest site. In someembodiments, the device can sense the proper force on the leg beforeallowing the actuating of the needles.

FIG. 7A depicts at step 700, a disposable package 702 containing adisposable array 704 and a disposable strap 706 and a base 708.Disposable array 704 contains the needles for harvesting tissue from thedonor site. At step 700, disposable strap 706 and base 708 are removedfrom disposable package 702. At step 710 disposable strap 706 and base708 are applied to a patient, for example, to the patient's leg 712. Atstep 720, disposable strap can be tightened until an indicator 722 showsthat an optimal tension has been obtained.

FIG. 7B depicts fully opening disposable package 702 to allow a device732 to access disposable array 704. Step 740 shows device 732 clickingand locking into disposable array 704. Step 750 depicts device 732 anddisposable array 704 being placed into disposable strap 706.

FIG. 7C depicts a tissue harvesting sequence. A button 760 is pressed bythe user. Device 732 then maintains the appropriate force duringharvesting without further input or force from the user. The user simplywaits until the harvesting sequence is complete. FIG. 7D depicts removalof device (step 770), positioning of device with harvested tissue over awound (step 780) and scattering of harvested tissue over wound (step790). A user can press button 760 to scatter the harvested tissue fromthe needles onto the treatment site, as shown in more detail at 795.

While a strap has been shown in the above figures as the means forsecuring the device to the donor site, other means for securing thedevice also can be used. For example, in some embodiments, the devicecan be secured using an adhesive or a clamp. Further, in someembodiments, before insertion of needles into the donor site, the angleor perpendicularity of the device can be checked and adjusted to insurethat the tissue is not harvested at an angle. For example, the devicecan be kept to within +/−10 degrees from vertical.

In some embodiments, the device can have a force sensor. The forcesensor can detect the force with which the user is applying the deviceto the skin. Once the user has achieved what is considered an optimalforce, the device notifies the user that the optimal force has beenreached and that the user can begin deployment of the device. The devicecan use the force sensor to know that enough force has been appliedprior to harvesting. Alternatively, if the user is applying the force(with our without a strap), the device will check to be sure the user ispushing hard enough to successfully penetrate the donor site beforeharvesting. In some embodiments, the optimal force can be in the rangeof about 10 to 40 lbs. The device also can measure and monitor forcethroughout the harvesting sequence and can alert the user if a properforce is applied and/or if the force applied drops below an acceptablelevel. The alert can be visual or audible.

In some embodiments, the strap can contain multiple ports for access tomultiple harvesting sites. In these embodiments, a throw-away shield canbe included in each port on the strap, which can attach itself to thecartridge after harvesting. The purpose of the throw away shield is toprevent contamination of the donor site when going back to harvest asecond time if the cartridge comes in contact with the wound duringscattering. The user can then dispose of the throw-away shield beforeharvesting again at a second port and again at additional ports. Thethrow away shield also prevents a user from going back into the sameport twice, e.g., harvesting from the same area twice.

Vibration Assisted Coring

In some embodiments, vibrating the needles upon entry into the donorsite can help reduce needle insertion forces and accordingly reducedamage to tissue and pain to the patient. FIG. 8A depicts an apparatus800 for the vibratory actuation of a needle. FIG. 8A depicts threestates of the same configuration, first state 802/804, second state810/812, and third state 820/822. For each state, a top view (804, 812,822) and a side-sectional view (802, 810, 820) are shown.

In some embodiments, apparatus 800 can include an oscillating strikeplate 803 which surrounds a needle 805 by means of a contact aperture806. Strike plate 803 can be supported by one or several plate supports807, which permit and encourage the lateral or sideways motion of strikeplate 803 such that it may strike needle 805 one or several times peroscillation. In some embodiments, strike plate 803 may be set intooscillatory motion, and its motion maintained, by any of several means,including but not limited to piezoelectric, electromechanical,pneumatic, fluidic, mechanical, or magnetostrictive actuators 808. Oneor more actuators 808 may be employed. The schematic is intentionallynot drawn to scale; in practice, the amplitude of the vibration ofstrike plate 803 may be as small as several micrometers, but it may beconsiderably larger as well. In the first state 802/804, actuator 808actuates oscillating strike place 803 and causes a side of needle 805 tocome into contact with strike plate 803. In second state 810/812, strikeplate 803 has moved away from actuator 808 and is centered around needle805. In third state 820/822, strike plate 803 comes into contact withthe opposite side of needle 805. In some embodiments, strike plate 803can be composed or metal or plastic.

In this embodiment, strike plate 803 and needle 805 are independentlymounted and mobilized. That is, needle 805 may be moved independently ofstrike plate 803. For example needle 805 may be translated vertically(up or down) through contact aperture 806, without any need to translatevertically strike plate 803 and its supports 807. Further, as shown inFIG. 8A, the energy of actuator 808 is directed into strike plate 803rather than directly into needle 805. This permits the design andselection of specific vibratory properties for strike plate 803assembly, such as resonant frequency, independent of the needleactuation schemes.

Five general methods of coupling the actuator to the strike plate areshown in FIGS. 8B-8F. It will be understood that a single actuator and asingle needle are shown for illustrative purposes, but that the schemesmay be extended to include several actuators and several needles, asshown in FIG. 8G. FIG. 8B depicts vibratory actuation system in firststate 802, second state 810 and third state 820, actuator 808 secured toa stationary base 830 and is loosely coupled to the strike plate 803 orits support structure 807. The free-end of the actuator intermittentlycontacts the strike plate (or a portion of its supporting structure).The resonant properties of the strike plate and its supporting structureare independent of the actuator. The contact point of the actuator maybe such as to effect amplification of displacement. For example, in FIG.8B, the actuator makes contact at an intermediate point between the nodeand anti-node of vibration of the plate support. The motion of thestrike plate may be such as to contact the needle once per oscillation,twice per oscillation (as shown in the FIG. 8B), or multiple times peroscillation. The energy of the actuator may be conveyed to the point ofcontact via a waveguide 832 or similar transmission element, which mayalso include displacement amplification, as shown in the second figurebelow.

FIG. 8C depicts vibratory actuation system in first state 802, secondstate 810 and third state 820, in an arrangement where actuator 808 issecured to a stationary base 830 and is tightly coupled to strike plate803 (shown at top row 836) or its support structure 807 (shown at bottomrow 838). The actuator (or a waveguide extension of the actuator) isattached to the strike plate 803 or to the strike plate supportstructure. Non-resonant vibrational modes may be excited with greatercontrol than with the loosely-coupled scheme. The actuator may besimultaneously employed as a sensor, and as a result, vibrationalfeedback control becomes possible. In FIG. 8C, while the actuator isattached to the strike plate, it does not travel with the strike plate.In some embodiments, it is also attached to a fixture that issubstantially heavier than the strike plate (the device handle, forexample), so that this other fixture is essentially “stationary.” Thisway, the strike plate only moves exactly the way the actuator is movingit the frequency and amplitude of oscillation can be controlled.

FIG. 8D depicts vibratory actuation system in first state 802, secondstate 810 and third state 820, in an arrangement where actuator 808 istightly coupled to the strike plate 803 (shown in top row 840) or itssupport structure (shown in bottom row 842), and actuator 808 travelswith strike plate 803. In this embodiment, very low mass schemes arepossible and complex modes of vibration are typical. In someembodiments, a lower mass scheme refers to the actuator not beingattached to something substantially heavier to stabilize it. In thisscheme, the actuator is attached only to the strike plate. Complex modesof vibration refer to modes more complex than a simple wave patternbecause the strike plate and actuator move together, so complex modeswould occur as multiple waves interacted with each other.

FIG. 8E depicts vibratory actuation system in first state 802, secondstate 810 and third state 820, in an arrangement where actuator 808 isas secured to a stationary base 830 and is energetically coupled 850 tothe strike plate 803 or its support structure 807 through transducer 852without physical contact. Any of several means of energy transfer arepossible, including inductive, electrostatic, acoustic, and pneumatic.Depending on the technology used, transducer 852 could be piezo, EMF,magneto, mechanical, or another type of transducer.

FIG. 8F depicts vibratory actuation system in first state 802, secondstate 810 and third state 820, in an arrangement where actuation iseffected indirectly, as a consequence of the general vibration of theassembly 860. The strike plate 803 and associated structure 807 isdesigned to vibrate harmonically when the overall assembly is jarred,for example, by the action of a solenoid elsewhere within the assembly,or by the action of a spring and ratchet mechanism elsewhere within theassembly. In some embodiments, vibration of the strike plate 803 may besynchronized with other actions or operations of the assembly. In someembodiments, vibration of the strike plate 803 may be triggered manuallyor automatically.

Operational Modes and Configuration

For any of the above described schemes, vibrational modes may beselected to be resonant or off-resonant. In some embodiments, vibrationmay be effected in conjunction with other operations. For example,vibration may be applied intermittently and briefly, as required, inconjunction with an impulse energy source, such as a solenoid, that maybe applied directly to the needle. In some embodiments, feedback control(for those instances where the actuator is simultaneously used as asensor), may be used to control the duration and timing of vibrationalactuation. Further, frequency and displacement amplitude may be selectedover a very wide range: sub-sonic, sonic, and ultrasonic.

Vibration assistance may be effected for needle advancement, retraction,or ejection of cored material. In some embodiments, the contact apertureof the strike plate may be shaped to effect one contact per oscillationor several contacts. The roughness and/or sharpness of the aperture maybe configured to influence the quality of the resulting vibration of theneedle. Further, in some embodiments, the position of contact betweenthe strike plate and the needle may be selected to influence theamplitude and mode of vibration of the needle.

In some embodiments, the strike plate and its associated structuralcomponents may be designed to oscillate as a result of direct orindirect actuation, and actuation may be effected manually orautomatically (electronically). Direct actuation includes, but is notlimited to, vibratory sources such as piezoelectric elements,magnetostrictive elements, electromagnetic solenoids, mechanical springsand ratchets, pneumatic bursts, fluidic oscillations, acoustic energy,etc. Indirect actuation includes any jarring motion of the entireassembly that might be effected by means, for example, of a solenoidaction. Thus, the advancement or retraction of the needles by means ofsome mechanical action may be used to simultaneously induce avibrational oscillation of the strike plate, which would then impartvibration to the needle. Direct actuation schemes include methods ofphysical contact as well as methods of non-contact. For example, theactuator may be positioned remotely from the strike plate, and thevibrational energy of the actuator may be conveyed to the strike plateor to its structural components by direct contact with flexiblewaveguides, or without contact via electromagnetic induction,magnetostrictive induction, or acoustically through the air.

FIG. 8G depicts the use of an oscillatory strike plate 803 to a needlearray 870, according to some aspects of the present disclosure. Thestrike plate 803 may be configured to impinge upon a 1D or 2D array ofneedles 870. Any single needle or multiple needles may be moved into orout of the contact apertures at any time.

Modes of Oscillation

FIG. 8H depicts two modes of operation of the vibratory actuationsystem. Depending upon several parameters (the number, positions, andsequencing of actuator elements, the shape and mass of the strike plate803, the stiffness and orientation of the flexible supports, etc.), thestrike plate 803 may be oscillated over a wide range of motions,including simple linear (shown at left 880) to a phased quasi-circularmotion (shown at right 890). Linear mode 880 contains one actuator 808that moves in a single linear plane, shown as A⇄B. Phased quasi-circularmode 890 can have three actuators 808, where each actuator can move inseparate planes A, B, and C. The vibration in FIG. 8H is perpendicularto the axis of the needles; however, it does not need to be. Thevibration could be applied in any direction, including in the axis ofthe needles. One way to vibrate along the axis of the needles can be tosend very short and quick signals to the solenoid, thereby “chattering”it.

Stem Cells/Fat Tissue

The described micrografts can include skin tissue that can include,e.g., epidermal and dermal tissue, and/or tissue obtained from otherbody organs. The micrografts can have at least one dimension that isrelatively small, e.g., less than about 1 mm, or less than about 0.5 mm,or optionally about 0.3 mm or less, or about 0.2 mm. Such exemplarysmall dimensions of the micrografts can facilitate both healing of thedonor site following harvesting, and viability of the micrografts byallowing greater diffusional nourishment of the micrograft tissue. Thesmall regions of damage in the donor site caused by a removal of thetissue portions can heal rapidly with little or no formation of visiblescars. The micrografts obtained from skin tissue can include, e.g.,epidermal and dermal tissue, and can also include stem cells that can belocated proximal to the dermal/fatty layer boundary.

An exemplary micrograft can have an elongated shape that may beapproximately cylindrical. The micrografts can include both epidermaltissue and dermal tissue from the exemplary donor site. For example, theexemplary micrograft can be about 3 mm in length, which can correspondto a typical total depth of the skin layer (e.g., epidermal and dermallayers). A different length may be used based on the particular skin ortissue characteristics of the donor site. In prior applications, it hasbe noted that it can be preferable to avoid harvesting a significantamount of subcutaneous tissue, so the harvested micrografts can includeprimarily the epidermal tissue and the dermal tissue. For example, priorart techniques for performing skin grafts remove or scrape off anyadipose or fatty tissue from a skin graft before applying the graft to awound site. This has been done because the fatty tissue is generallyseen as a by-product of the harvesting process that adversely interfereswith the ability of the grafted skin to access the blood supply at thewound site. Therefore, in prior methods, all fatty tissue is cleavedfrom the graft.

However, according to aspects of the present disclosure, because of thesmall size of the micrograph columns, these columns generally cansurvive at the wound location via diffusion without having to form agood connection to the blood supply at the wound location. Accordingly,it may be helpful to include subcutaneous tissue in the micrograft, asadipose tissue in the subcutaneous tissue contains stem cells. Thus, ifthe depth of the micrograft can extend to a lower portion of the dermallayer of the donor site (e.g., near a dermal/fatty layer boundary) andeven into the dermal/fatty layer boundary, the micrografts can includestem cells, for example, mesenchymal stem cells. These stem cells canfacilitate healing and integration of the exemplary micrografts whenthey are scattered or inserted into a recipient site.

Additionally, prior art methods of harvesting adipose-derived stem cellshave required isolating and purifying the stem cells from the adiposetissue. See e.g., U.S. Pat. No. 6,777,231 to Katz. However, according toaspects of the present disclosure, the healing benefits of the stemscells can be realized without processing, isolation or purification ofthe stem cells. The presence of the stem cells within the fatty tissueof the micrograft alone can result in increased healing and integrationof the micrograft. Accordingly, it may be beneficial in include at least5% or 10% of fatty, adipose tissue in the micrografts to realize thebenefits of the stems cells at the recipient site. Therefore, accordingto some embodiments of the present disclosure, the micrografts can be upto 4 or 5 mm in length to access the adipose cells in the fatty tissuelayer.

Rotation and Actuation of Needles

In some embodiments, individual needles can be rotated. This can beeffected by rotating the full array of needles through the use of gearsor o-rings, or any other means of rotation. The rotation of the needlesupon entry of the needles to the donor site allows for low force coringof the skin. In some embodiments, the use of rotation allows for thebetter use of straight cut, sharpened edges of the needles.

In some embodiments, the needles can be driven into the donor site usingan electric hammer. This electric hammer can have a rotating cam thathits a plunger to move the needles multiple times per second. In thisembodiment, the use of the automatic hammer can drive the needles intothe donor site more gradually than the solenoid actuation.

In further exemplary embodiments of the present disclosure, theexemplary methods and apparati described herein can be applied to othertissues besides skin tissue, e.g., internal organs such as a liver orheart, and the like. Thus, grafts can be formed for a variety of tissueswhile producing little damage to a donor site and facilitating rapidhealing thereof, while creating graft tissue suitable for placement atrecipient sites.

The subject matter described herein can be implemented alone or inconjunction with a system that facilitates removal of tissue from adonor site, and/or scatters or otherwise disposes tissue at a recipientsite or other site. It is to be understood that the disclosed subjectmatter is not limited in its application to the details of constructionand to the arrangements of the components set forth in the precedingdescription or illustrated in the drawings. The disclosed subject matteris capable of other embodiments and of being practiced and carried outin various ways. Also, it is to be understood that the phraseology andterminology employed herein are for the purpose of description andshould not be regarded as limiting.

As such, those skilled in the art will appreciate that the concept, uponwhich this disclosure is based, may readily be utilized as a basis forthe designing of other structures, methods, and systems for carrying outthe several purposes of the disclosed subject matter. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe disclosed subject matter.

Although the disclosed subject matter has been described and illustratedin the foregoing exemplary embodiments, it is understood that thepresent disclosure has been made only by way of example, and thatnumerous changes in the details of implementation of the disclosedsubject matter may be made without departing from the spirit and scopeof the disclosed subject matter.

The invention claimed is:
 1. A device for obtaining biological tissuecomprising; an array of hollow tubes, the array comprising a first rowof a plurality of hollow tubes; a second row of a plurality of hollowtubes, adjacent the first row of hollow tubes; a third row of aplurality of hollow tubes, adjacent the second row of hollow tubes, thefirst, second and third rows forming an array of hollow tubes; whereineach hollow tube comprises two points at the distal end of the hollowtube, the plurality of rows forming a two dimensional array of hollowtubes; wherein the two points are formed by a first bevel on a firstexternal side of an outer surface of the hollow tube and a second bevelon a second external side of an outer surface of the tube opposing thefirst side of the hollow tube; the first bevel having at least two anglesections including a first shallow angle section to form a first narrowheel and the second bevel having at least two angle sections including asecond shallow angle section to form a second narrow heel; the arraycomprising a circle having an area of about one square inch; wherein aninner diameter of each hollow tube is less than about 1 mm, the distalend of each of the hollow tubes is configured to be inserted into abiological tissue donor site to remove a portion of tissue therefromwhen each of the hollow tubes is withdrawn from the donor site; whereinthe array comprises a sufficient number of hollow tubes to withdrawabout 0.1 square inches of tissue from the donor site with a singleinsertion of the array; a first solenoid, wherein first the solenoidactuates at least a first row of hollow tubes to insert at least thefirst row of hollow tubes into the biological tissue donor site.
 2. Thedevice of claim 1, wherein the donor site comprises an area of about onesquare inch.
 3. The device of claim 1 wherein the array of hollow tubescomprises about 300 hollow tubes.
 4. The device of claim 1 comprising: aplurality of pins, each of the pins provided within a central lumen ofeach of the hollow tubes.
 5. The device of claim 1, comprising a stop tolimit the depth of insertion into biological tissue of each of thehollow tubes in the array of hollow tubes.
 6. The device of claim 1,comprising a second solenoid, wherein the second solenoid actuates in adirection opposite the first solenoid.
 7. The device of claim 1,comprising a force sensor, wherein the force sensor senses the forcewith which the device is applied to the biological tissue donor site. 8.The device of claim 1, wherein the first narrow heel comprises less thanabout 10% of the inner diameter of the hollow tube and the second narrowheel comprises less than about 10% of the inner diameter of the hollowtube.
 9. The device of claim 1, wherein the hollow tube has an innerdiameter of less than about 0.8 mm.
 10. The device of claim 1, whereinthe biological tissue comprises skin tissue and adipose tissue.